The structural organization and function of oral epithelium is, in part, dependent on a steady and adequate supply of various nutrients. The objective of this proposal is to investigate the role of two dietary constituents viz. protein and zinc, in the maintenance of the homeostasis of oral epithelium. To achieve this end we intend to use an experimental animal model to determine the separate effects of protein and zinc deficiency on the fundamental processes of cell proliferation and maturation in oral epithelium. With respect to cell proliferation, the effects of the two nutritional deficiency states on the duration of DNA synthesis and mitosis, and turnover time will be studied. In regard to the maturation process in oral epithelium, the alterations in protein synthesizing capacity, keratohyaline granules and lysosomes will be investigated. The methodological approaches include autoradiography at the light microsopic and ultrastructural level, and biochemical and cytochemical techniques. An understanding of the role of two key nutrients, protein and zinc, or important events in the cell cycle and maturation of oral epithelial cells should advance our understanding of the manner in which these two nutrients exert their influence on the biology of the lining tissue of the oral cavity.